I’m getting ready to build a sandbox to go in my parents backyard for all the grandkids to play in. Was considering using a composite decking material like Trex or something and wanted to see if anyone has done this before. Wanted to stay away from pressure treated wood if possible and didn’t want to have to keep applying a finish every year or so. Anyone else build a sandbox years ago? How’s it holding up? Also, on a related note, anyone know how many cubic feet 50 lbs. of sand is? Trying to figure out how much sand I need as well. Thanks in advance for you help.

5 replies so far

I haven’t built a sandbox, but my dad built one for us as kids. He used old railroad ties, then used creosote to preserve them. I know, creosote is absolutely terrible, but back then, that’s what worked well.

I’d definitely consider and likely choose Trex, or an equivalent to build a sandbox. Not only will it not need any maintenance, but you’ll avoid any splintering issues that could occur with wood. Just make sure to use the proper screws (which I’m sure you knew already). I’m assuming you could also predrill larger holes, then anchor the composite material into the dirt as you would with timbers.

How big is the sandbox going to be? I’m asking because if you go to the box store and buy the sand by the bag, it should list how much cubic material is in the bag. If you’re having it delivered or hauling it yourself, the yard you get it from should be able to provide you with an accurate cubic footage or cubic yard/scoop.

-- Jonathan, Denver, CO "Constructive criticism is welcome and valued as it gives me new perspectives and helps me to advance as a woodworker."

Thanks for the response Jonathan. Yeah, I did find that most composite decking manufacturers recommend you use special composite decking screws. As for the size, not too large. Maybe 6’ x 6’. And doing a little more research it seems 1 50 lbs. bag is about 0.5 cubic feet or about 6 square feet 1 inch deep.